Exhaust silencer



Sept- 22, 1935- R. DE H. sT. STEPHENS EXHAUST SILENCER Filed Dec. 2, 1935 Patented Sept. 22, 1936 oNiTED] STATES PATENT OFFICE 2,054,955 l EXHAUST SLENCER British kCompany Application December 2, 1935, Serial No. 52,598 In Great Britain February 28, 1935 3 Claims. (Cl. 181-44) This invention relates to exhaust silencers more particularly for pneumatic drills but applicable also to internal combustion engines for example, of the kind in which the exhaust is divided into two sets of streams or jets which are opposed to one another so that the streams or jets meet together before passing out of the silencer.

According to the present invention the passages for the two sets of streams or jets are provided by notches or grooves in the peripheries of a pair of partitions which t closely within a casing constituting the silencer chamber.

Preferably, the two partitions are constituted by two parts of a single annular casting which occupies the annular space between the exhaust pipe and a surrounding casing, the exhaust pipe being provided with a plug and with holes on either side of this plug, the holes in front of the plug allowing the exhaust to enter the casing and the holes beyond the plug allowing the exhaust after it has passed through the two ,sets of passages or jets to escape through the open end of the exhaust pipe. The casting is formed with apertures through which the exhaust can pass to the part of the casing beyond the casting.

An embodiment of the invention suitable for use with pneumatic tools is illustrated by way of example in the accompanying drawing, in which Figure l is a side elevation of the silencer in section, and

Figure 2 is a cross-sectional end elevation on the line II-II in Figure 1.

A preferred embodiment of the invention will now be described by way of example. In this embodiment a cylindrical barrel IG is secured to annular end plates l2 surrounding the exhaust pipe I4 so as to constitute an exhaust chamber concentric with the exhaust pipe. Within this chamber, and occupying the whole of its cross-section, is a casting I6 in the form of two hollow conical parts with their bases turned towards one another but spaced apart, and united by three tubular portions I8 equally spaced around the exhaust pipe. The small diameter ends of this casting are bored to fit the exhaust pipe, or rather to fit a separate section 2 of this pipe, the front end of which is closed by a plug 22. The central large diameter parts 2li of the casting are made cylindrical and t tightly within the barrel l0 and these cylindrical parts are formed with a number of spaced notches 26 which provide passages closed on their outer sides by the inner surface of the barrel.

In front of the plug 22 the wall of the exhaust pipe is pierced with a number of holes 28 through which the exhaust from the tool or 5 engine can enter the casing. Some of the exhaust passes through the notches 26 in the periphery of the left-hand or leading half of the casting i6, and another part passes through the tubular portions i8 of the casting into the l0 part of the casing beyond the casting from which it iiows through the notches 26 in the periphery of the right-hand portion of the casting. The exhaust is thereby divided into a number oi separate streams or jets which meet l5 together in the free space within the casting. From there the exhaust enters the pipe 2t beyond the plug 22 through holes 36 in its wall and escapes through the open end of this pipe.

The separate section 2G of the exhaust pipe which supports the casting is of smaller diameter than the exhaust pipe proper i4 and has a shouldered portion 32 which fits within the end of the latter, this end providing a shoulder against which the end of the casting abuts. rlhe 25 other end of this smaller diameter part 20 of the exhaust pipe is screw-threaded externally to receive a screwthreaded sleeve 35i which serves for the attachment of the final section 36 of the exhaust pipe the end of which beyond the 30 exhaust chamber is open freely to the atmosphere.

In a modified construction the pipes i4 and 2U are of the same diameter and are screwed into the lbore in the left-hand end of the casting I6.

I claim:

l. An exhaust silencer comprising a casing, an exhaust pipe extending centrally through said casing, two partitions extending across the annular space between the exhaust pipe and the casing and enclosing a compartment between them, each of said partitions being formed with a series of notches in its periphery forming passages bounded externally by the internal surface of the casing, a plug within the exhaust pipe in the region of one of the said partitions and conduits extending between said partitions and establishing communication with the parts of the interior of said casing external to said compartment, the exhaust pipe being formed with holes in that part of it which is in advance of the plug and also in that part of it which is within the compartment.

2. An exhaust silencer comprising in combination a casing, an exhaust pipe extending centrally through said casing, an annular casting occupying the annular space between the exhaustV pipe and the casing, said casting comprising two partitions enclosing between them an annular compartment and a plurality of tubular conduits extending between the partitions, the peripheres of both partitions being formed with a series of notches bounded externally by the internal surface of the casing, said exhaust pipe being plugged in the region of one end of said casting and being perforated to provide communication between it and the interior of the casing in advance of the plug portion and also to provide communication from the interior of said compartment to the part of the exhaust pipe beyond the plugged portion. Y

3. Exhaust silencer comprising a casing, two partitions within said casing dividing it into three compartments, each of said partitions being formed with a series of notches in its periphery forming passages bounded externally by the internal surface of the casing, means for leading exhaust gases into those two of the said compartments that are external to the partitions and means for leading out of the compartment enclosed between the partitions exhaust gases which enter said compartment through the passages aforesaid from the other two compartments.

RAYNAR DE HELE ST. STEPHENS. 

